7mgte turbo upgrade?

[pozman]

Hi guys, I have a 7mgte in my bundera. I'm looking at replacing the ct26 with a Garrett ball bearing turbo

I'm NOT looking for big power. More would be good tho. I'm looking for faster spool time with out loosing top end

so really some thing similar sized to the ct26 I suppose

I was oringaly thinking something in the gt30 range but think they will be too large for what I'm chasing

so maybe gt2871r or gt2876r?

Any help would be great

Paul

[Kedderz]

For me a 3076r would be the best bet, a 28 series unit will be too small for the 3 litre engine. Check out the compressor maps for each turbo on garrett's website and make an informed decision from there ;-)

[pozman]

yeah that was what i was originally thinking, but i was speaking to a bloke that had one on a rb25 and he wasn't making boost until around 4500rpm?

i know with a 3lt it will spool a bit quicker, but not enough to be usable for my application

[boxh34d]

What sort of mods have you done to your 7M, and what are you aiming for? I know you say not big power, but what sort of figures are you trying to achieve.

[pozman]

its been fully rebuilt, only to standard spec, with head stud kit, 3in straight through exhaust, custom airbox

only running around 7psi boost atm as no cooler on it but will go up to maybe 15ish

have got large(ish) intercooler that hasn't been put on yet

not sure what looking for power wise, its already fast for a 4wd (ripping dunnydoors in a jacked up 4wd is ace) but its more for turning larger tyres down low

so similar sized, maybe slightly larger turbo, trying to get rid of some lag

[boxh34d]

Just a few experiences from my experimenting early on.
Intercooler would definately help for a start.
I found my CT26 ran out of puff at around 12 to 13psi @ around the 215kw mark. However, we did a fair bit to get there.
I assume you've got a standardish dump pipe setup. When I put my divorced setup on (about 18 inchs long to the merge), I gained about 300rpm worth of boost response with that alone in my MA71, compared to the std dump, and a 3" down pipe and full exhaust. You would probably spool earlier too, due to the added drag of the big tyres making the engine load up.
Also, I can't recommend an aftermarket ECU highly enough. We were able to hold the wastegate closed until desired pressure, pull a heap of fuel out, and dial a shitload of timing into the thing early in the rev's, and the difference in low down urge was huge!
From memory, if I loaded the thing up a bit, I could get 5 odd PSI at around 1900RPM.
I certainly think there is more response to be had with a decent manifold setup, and a nice new BB turbo, but there is a metric shitload that can be done with the standard setup if you can get the fuel and ign working for you.
Some food for thought.

[pozman]

thanks for the info mate, yeah i really need to get the cooler on, but haven't been sure on whether to put it on before or after engineering

filled my clutch with muddy water the other day, so going to get a hd one to replace it, so turbo has been put off for a while

still have know idea what to get tho

[pozman]

been doing a lot of research lately, and found a good article on boostcruising, and garretts tech stuff on there site

i will be looking at this stage at a gt3071r, the one with the t3 housing, (60mm rear wheel), apprantly they give great spool response, and has a well matched compressor map (only quick look atm, got to really go thru the maths)

but for now im going to do a few more things with the ct26 see what i can get out of it, bought a good dump pipe last night, will put cooler in and get high flow cat

thanks again for the info

[TheStitt]

I ran a high flowed CT26 on my crown there are some comparison pics of the high flowed vs not in my build thread,

came on really early and pulled like a train